Manometric apparatus



Aug. 29, 1933. c, BOULJTTE 1,924,104

muoum'ran: APPARATUS Filed March 12, 1.932 I 2 Sheets-Sheet. 2

L INVENTOR GEarye; Cza /e: 301/??? Patented Aug. '29, 1933 UNITED STATES PATENT OFFICE Application March 12, 1932, Serial No. 598,452, and in Belgium July 2, 1931 4 Claims.

The invention relates to manometric apparatus for measuring or observing pulsating pressures, and it relates more particularly to sphygmographs, sphygmomanometers, or sphygmometro- 5 graphs for observing or measuring arterial pressure. However, the invention is not limited to any particular type of manometric apparatus.

The primary object of the present invention is to provide a manometric apparatus with which more precise and more rapid measurements may be made.

According to the present invention, there is provided at least one enclosure which is filled with a fluid which may be caused to exert pressure against a flexible diaphragm which cooperates with appropriate recording members to record the pressure exerted thereon by the fluid. If such an apparatus is connected to a source giving rise to a pulsating pressure, such, for example, as one of the arteries of the human body, the force exerted on the fluid within the enclosure by the pulsating pressure will be transmitted through the diaphragm and recording members and a record will be made of the amplitude of the pulsations.

In order that it will be possible to observe or record in a continuous manner the amplitudes of the pulsating pressures to be studied, the average pressure exerted by the fluid within the enclosure should be either greater or less than that of the pulsating pressure, and to that end means are provided for increasing or decreasing the pressure normally exerted on the diaphragm by the fluid within the enclosure, and to permit a continuous 5 and uniform increase or decrease of that pressure. While various means may be provided for changing the pressure exerted in the diaphragm by the fluid within the enclosure, I prefer to accomplish the change by means which will cause a'continuous and uniform decrease of that pressure. Such means may conveniently comprise a tube or a nest of tubes which are connected to the enclosure or enclosures and have their lower ends immersed in a tank filled with a liquid, preferably one having a high specific gravity, such as mercury. As the degree of immersion of said pipes changes, the pressure exerted by the fluid in the enclosure changes in a direct ratio; thus, if the tubes are so mounted with respect to the tank containing the liquid in which they are immersed that the degree of immersion is continu- ,ously and uniformly decreased, the escape of the fluid within the tubes through their ends will cause the pressure exerted against the diaphragm to be continuously and uniformly decreased.

The invention will be further described in connection with the accompaying drawings, which disclose embodiments suitable for use with sphygmographic apparatus, but it is to be understood that this further disclosure and description is an exemplification of the invention, and the same is not limited thereto except as is specifically pointed out in the appended claims.

In the drawings:

Figure 1 is a diagrammatic view, partly in sec;- tion and partly in plan, of a sphygmographic apparatus embodying the invention, and

Figs. 2 and 3 are similar views of modifications.

While the apparatus of the present invention 7 may comprise only a single enclosure, I prefer to provide two adjacent enclosures a, and b which are separated by a membrane or diaphragm a.

As shown in Fig. 1 the enclosure a is connected directly to a cuff d which may be placed on one of the arms of the person to be examined. The other enclosure is connected to a conduit 1, which has its other end connected to a pressurealtering means, such as a piston pump e. The conduits c and f are connected by a branch conduit 9 having a valve h therein. By means of the pump e air may be forced into the conduits f, g and 0 whereby the pressure exerted on the diaphragm by the fluid in the enclosures a and b may be either raised or lowered to an initial value higher or lower than the maximum or minimum value of the arterial pressure to be studied. As soon as the desired initial pressure is attained, the valve It may be closed to isolate the enclosures a and b from one another.

As the enclosures a and b are separated by the flexible diaphragm, any differential in pressure in either enclosure will cause a displacement of the diaphragm. Such displacement of the diaphragm may be transmitted to a suitable recording or indicating member in order that a record or indication of the displacement may be obtained. Thus, pulsations in an arterial stream may be transmitted through the cuff d to the fluid in the enclosure a to cause a vibration of the diaphragm a. Those vibrations, in turn, cause the operation of the recording or indicating means to give a record or indication of the amplitude of the pulsations being studied. If merely an indication of the pulsations is Wanted, the diaphragm may cause a needle or pointer to move over a dial. However, as a permanent record for future consideration is generally desirable,

I prefer to connect the diaphragm through suitable operating levers to a recording stylus h capable of movement axially with respect to a cooperating rotating drum 2', onto which a record of the amplitude of the pulsations may be made. The operating levers may pass through the walls of the enclosure in a manner such as is disclosed in French Patent No. 19,698.

While enclosures a and b are both shown as comprising three rigid walls and a common displaceable diaphragm separating them, the apparatus may be modified by having the enclosure 2), for example, in the form of a deformable cap sule.

In order that a contnuous record curve of the amplitude of the pulsations may be obtained, means are provided for obtaining a gradual and uniform increase or decrease of the initial pressure prevailing in the interior of the'enclosures a and 1), depending upon whether the initial pressure in the enclosure is higher or lower than the pulsating pressure to be studied. If the pulsating pressure is higher than that initially prevailing in the enclosures, the pressure therein will be gradually and uniformly decreased, but if the pulsating pressure is lower than the initial prevailing pressure in the enclosures, the pressure therein will be gradually and uniformly increased. The means for increasing the pressure within t e enclosures is so arranged that the valve I may be maintained closed, and. the enclosures a and b isolated. 7

Assuming that the pulsating pressure to be studied is greater than that initially prevailing in the enclosures, a and b, and it is desired to gradually and uniformly decrease the pressure in the enclosures, the enclosures a and b are connected respectively by conduits a and b to means which will simultaneously bring about a diminution "of the pressure in the enclosures. Such means may comprise two exactly calibrated stop cooks, the movements of which are conjugated to one another, or two spring valves the opening and closing of which is controlled by uniformly decreasing the tension on the springs by a unicontroi cooperating with the two valves, as for example, a weight movable along a lever arm, or preferably as shown in Fig. l, in which the ends of the conduits a and 2) remote from the enclosuresc and To enter at the same horizontal plane into a liquid having a high specific gravity, such as mercury, contained in a tank is. The hydrostatic pressure of the liquid in the tank 7c exerting its force on the open end of the tubes, balances the pressure in the enclosures. By using mercury, or some other liquid having a high specific gravity, an apparatus having less cumbersome dimensions will sufiice, since the'column of liquid in the tank It need not be near so high as if the liquid were one having a lower specific gravity.

To enable a continuous and uniform decrease in the degree of immersionof the ends of the con-' duits, means are provided for causing relative vertical movement between the ends of the conduits and the tank, either by maintaining the tank fixed and displacing the ends of the conduits thereto, or, as shown in Fig. l, by maintaining the tubes fixed and moving the tank relative to them. As shown in this figure, the tank it containing the liquidin which the ends of the conduits a and b are immersed, is suspended by a cable I passing around pulleys m and having a weight n on its other end for partly balancing the weight of the tank and its contents. A relatively slow and uniform lowering of the t .such chambers will be filled with a liquid of modmosaics may be obtained by means of a suitable centrifugal regulator or wind damper p.

As the tank It descends air will escape from the enclosures a and b. As soon as the degree of immersion of the conduits a and b is'such that the hydrostatic pressure exerted by the liquid therein is no longer sulficient to balance the pressure initially prevailing in the enclosures a and b, the escape of air from the enclosures a and in through the conduits a and b and the liquid in the tank is will continue uniformly, and consequently bring about a uniform decrease in the pressure in the enclosures as long as the tank It continues to descend. As an almost instant and regular escape ,of the air bubbles from the ends of the conduits a andb' is desirable, so that a well determined pressure inside the enclosures corresponds to each position of the tank, the end portions of the conduits a and b are preferably formed by nests of tubes g which may comprise the same number for each conduit if the capacity of enclosures a and b is about the same, or, if the capacity of the enclosures is substantially different, the number of tubes at the ends of the conduits a and b may be different, or the tubes may be of different cross sections.

When desired, intermediate expansion chambers may be inserted intermediate the ends of the tubes a and b as shown in Fig. 2. When used,

erate density, such as water, so that the escape of gas from the enclosures a and b can be regulated.

with the apparatus. as described above, there may be combined suitable means to, constantly or at intervals, indicate the degree of pressure existing in the enclosures. To that end, one wall of the tank It is provided with a plurality of .regularly spaced contacts s2 which are adapted to contact with a fixed contact 8 to complete an electrical circuit including an electromagnet 12 As the tank It descends, the contacts s2 will progressively come into contact with the fixed contact s, and each time a contact s2 contacts with contact. s the circuit through the electromagnet 1' will be completed and a recording 0 stylus r operated to mark in abscissae, with respect to the curve representing the amplitude of the pulsations which is represented in ordinates, the pressure then prevailing in the enclosures a and b.

As also shown in Fig. l, the shaft on which the drum i rotates is mechanically connected to the means for regulating the speed of descent of the tank is, so that the descent of the tank and the rotation of the drum is conjugated, whereby the scale of the abscissae will represent the pressure in the enclosures, while the scale of the ordinates will represent the amplitude of the pulsations.-

The modification shown in Fig. 3 is adapted to operate with a cuif having a plurality of pocketsf instead of with but a single pocket as shown in Fig. i. In Fig. 3 two pockets (1' and d2 are shown. The pocket d is connected with the enclosure a in the manner described in connection with Fig.

The second pocket is connected by the conduit g to pump e, and also is in communicationwith conduit (121 which is immersed in tank is the same as conduits a and b. The conduit g has a valve k2 therein, the movements of whichs are preferably conjugated with the movements of x the valve h in conduit 9 by means of a member n3 connecting the handles of the two valves. The valves are so set relative to the connecting member k3 that they are simultaneously opened 6 and closed.

When it is desired to chart the amplitude of a pulsating pressure, as for example the arterial pressure of a person, the tank la is raised to its upper position, the valve h or valves h and n2, depending upon whether the apparatus of Fig. 1 or Fig. 3 is being used, is opened and the pump e operated until a pressure of,say, for example, 30 cm. of mercury is attained in the enclosures a and b, and the cufi d, or cuffs d and d2. The valve or valves are then closed and the descent of tank It and the simultaneous rotation of drum iis started. With the apparatus thus operating the pulsations will be transmitted through cuff d, or cufis d and (12, to the rotating drum where they will be recorded on the drum i by the stylus h as ordinates, while simultaneous therewith the pressure existing in the enclosures will be recorded on the drum 2' in abscissae.

From the foregoing description, it will be apparent that with the present invention the method of recording pulsating pressures is immensely simplified, and that continuous curves may be obtained. Heretofore continuous curves have been difficult or impossible of attainment as it was necessary for the operator to handle alternately a separating member and an expanding member, so that for each operation of the expanding member there will be a corresponding line on the curve following the axis of the abscissae. Moreover, more precise curves can be obtained due to the fact that the inertia of the liquid in the tank will prevent modification of the value of the pressure as the two enclosures do not present any apparent reaction on one another.

I claim:

1. In an apparatus for measuring oscillating pressures, an enclosure, a diaphragm dividing the enclosure into at least two chambers, means for initially subjecting the opposite sides of the diaphragm to uniform pressures of a gaseous medium, means for communicatingoscillating' pressures through the gaseous medium to the diaphragm, means connected to the diaphragm to visibly translate movements thereof, and means for progressively and uniformly varying the gaseous pressure on opposite sides of the diaphragm, including conduits communicating with the chambers and a receptacle containing a liquid in which the ends of the conduits are immersed, the receptacle and the ends of the conduits being relatively movable whereby the hydrostatic pressure of the liquid with respect to the ends of the conduits is varied.

2. In an apparatus for measuring oscillating pressures, an enclosure, a diaphragm dividing the enclosure into at least two chambers, means for initially subjecting the opposite sides of the diaphragm to uniform pressures of a gaseous medium, means for communicating oscillating press'ures through the gaseous medium to the diaphragm, means connected to the diaphragm to visibly translate movements thereof, including a stylus and a moving surface co-operating therewith, and means for progressively and uniformly varying the gaseous pressure on opposite sides of the diaphragm, including conduits communicating with the chambers and a receptacle containing a liquid in which the ends of the conduits are immersed, the receptacle and the ends of the conduits being relatively movable whereby the hydrostatic pressure of the liquid with respect to the ends of the conduits is varied.

3. In an apparatus for measuring oscillating pressures, an enclosure, a diaphragm dividing the enclosure into at least two chambers, means for initially subjecting the opposite sides of the diaphragm to uniform pressures of a gaseous medium, means for communicating oscillating pressures through the gaseous medium to the diaphragm, means connected to the diaphragm to visibly translate movements thereof, means for progressively and uniformly varying the gaseous pressure on opposite sides of the diaphragm, including conduits communicating with the chambers and a receptacle containing a liquid in which the ends of the conduits are immersed, the receptacle and the ends of the conduits being relatively movable whereby the hydrostatic pressure of the liquid with respect to the ends of the conduits is varied, and means for visually indicating no with the chambers and a receptacle containing a liquid in which the ends of the conduits are immersed, the receptacle and the ends of the conduits being relatively movable whereby the hydrostatic pressure of the liquid with respect to the ends of the conduits is varied, and means co-operating with the moving surface to record the progressive variation of the gaseous pressure.

GEORGES CHARLES BOULI'I'IE. 

